Signaling system



Oct. 25, 1932. J. o. CARR ET AL 1,884,562

SIGNALNG' SYSTEM Filed May 27, 1930 5 Sheets-Sheet lv Oct. 25, 1932.

J. O. CARR ET AL SIGNALlNG SYSTEM Filed May 27. 1930 5 Sheets-Sheet 2 Oct. 25, 1932. .1. o. CARR E'r AL SIGNALING SYSTEM Filed May 27. 1950 5 Sheets-Sheet 3 2 oowfzla INVENTORSI JOHN O. GARR ABRAHAM S. BENAMN www L ATTORNY Patented Oct. 25, 1932A NI'TED STATES PATENT OFFICE JOHN 0. CARB AND S. THE TELETYPE CORPORATION, 'WARE BENJAMIN, OFCHICAGO, ILLINOIS, ASSIGNOBS TO OF CHICAGO, ILLINOIS, .A CORPORATION 0F DELA- BIGNALIN G SYSTEM application mea my a7, 19:0. v 'seran no. 456,207.

- at each station is usually supplied by motor mechanism. Where the signaling traliic conditions are such that the telegraph apparatus is substantially in continual use, these motor mechanisms are usually in normal operating condition. Where, however, the telegraph apparatus is used in connection with exchange systems and is only in actual use for intervals, it is desirable motor mechanism normally in a nonoperatmg condition to be started into operation automatically when, the printing apparatus thereat is connected for transmission and reception of telegraph code impulses.

In accordance with the present invention, calling devices are provided by which any subscriber may attract the attention of the operator at the central oliice exchange and connector devices or link circuits are provided by which vthe manual exchangeoperator may connect any two subscribers stations. Each such link circuit has a telegraph repeater associated with a source` of electric current in such manner that current is supplied to each of the connected lines. The circuit arrangements are such that the opening of the circuits of one line will open the circuit of its connected line by the functioning of the apparatus at the central oiiice, the source of electrical energy for operating the telegraph sets being locatedat the central exchange. The system thus becomes a cen- -ral battery system for the transmission of line signals and the telegraph station requires only a source of mechanical power for the operation' of the mechanical telegraph apparatus. For supplying the mechanicahpower at the telegraph station there is provided an: electrical motor driven by .any local source and controlled by'a relay responsive to currents in the telegraph lines.- This relay is controlled by .a polar relay responsive to re'- versals of potential in the telegraph line, the combination thus set up being a system of to maintain the motor starting controlled by reverse currents.

At the central oiiice other means is shown for 'the starting of the motor of the operators telegraph set whenever the motor is for service. Y

Accordingly, an object of our invention is to provide novel and eiiicient means for normally maintaining the motor mechanism of telegraph apparatus in non-operating condition, and for starting said motor mechneeded anism into operation automatically in re-A sponse to a telegraph connection.

Another object ofour invention is to provide novel means ina printing telegraph manual exchange system for automatlcally reversing the direction of current flow to a subscribers station in response to a telegraph communicating connection therewith, and for signaling with the said currents of reversed polarity .and or starting normally nonoperatin motor mechanism at the subscribers statlon into operation in response to said currents of reversed polarity.

A further object of our invention is to provide novel means ina manual telegraph exchange system for normally maintaining the motor mechanism of the subscribers apparatus in nonoperating condition and for starting said mechanism into operation in response to a telegraphic connection between ltwo subscribers.

A still further object of our invention is to provide novel means in a manual telegraph exchange system for maintaining a motor mechanism of each subscribers apparatus in a nonoperating condition, providing circuit connections whereby a subscriber may call the operator at the exchange or be called by the operator at the exchange over the same circuit over which telegraph signaling occurs and for simultaneously starting the normally 'nonoperating motor mechanism into operation in response to said call. Y

In printing telegraph signaling systems, provision is usually made for repeating the signals where the signaling lines are long.

In the case of manual exchange, it is preferable that these repeaters be provided in the Vexchange as part of the link circuits. These repeaters must be so arranged so that signals originating at any one station will be repeatcd to the other station. In order to prevent the repeater from transmitting signals back to the originating point, We have found special locking circuit arrangements must be made. Where the repeaters are plugged from one signaling line to another, We have also .found provision must be iliade to prevent false operation of the repeater while switching the repeater fromv one subscribers circuit into another.

Accordingly, a further object of our invention is to provide novel and effective repeater arrangements in a link circuit for a manual telegraph exchange.

Still another object of our invention is to provide simple and effective two-way repeaters for use in manual telegraph switching systems.

Other objects of the invention will be apparent from the following detailed description of preferred embodiments thereof and from the scope of the appended claims. Referring now to the accompanying drawings.

Figures 1 to 4` are diatic views showing four telegraph stations and their associated lines.

Figure 5 is a similar view illustrating the connective device ofthe record' type provided with its individual telegrap set.

Figure 6 is a diagrammatic view showing circuits of one form of repeater in detail,

Figure 6 is a diagrammatic view illustrating the potentiometer system employed in the re ater of Figure 6.

igure 7 is a similar view showing circuits of a modified form of repeater, 1

Figure 8 is a diagrammatic view showing a connective device with an individual telegr Fph set and a` jack for connecting the same,

igure 9 is a diagrammatic view showing a system of two connective devices and one operators set, each connective device having a manual key by which the operator may be connected.

v Figure 10 is a diagrammatic view'showing a further modied form of re ater.

Figure 11 is a preferred modification of the repeater shown in Figure 10.

Referring to Figure 1, a subscribers telegraph set is shown comprising a polar relay 10, a neutral relay 11, a printer magnet 12, a telegraph transmitter 13 and a key 14 all connected in series and a motor 15, controlled by the neutral relay 11. The polar relay 10 controls a shunt circuit around the neutral relay 11 which controls the energizing circuit for motor 15. The motor 15, when rotating, supplies the mechanical power for driving the subscribers printing telegraph apparatus (not shown) which is variably operated by the printer magnet 12 in accordance with received code combinations of impulse conditions received over line 16.

The line 16 connects the subscribers teletelegraph transmitter prising springs 18 and 19 and an intermediate spring 20. Line 16 is connected to spring 18,

Vspring 19 is connected through a resistance 21 to negative'battcry and spring 20 is connected to a line drop magnet 22 which in turn is connected through a resistance 23 to positive battery. lhe line drop magnet 22 controls a pivoted latch bar 24 normally urged toward retracted position by spring 24. The latch bar 24 engages the pivoted shutter 25 at one end as shown.

When the telegraph set is not in use the line circuit is normally closed and extends from dpositive battery through resistance 23, line rop magnet 22, spring 20 in engagement with spring 18, line wire 16, polar relay 10, neutral relay 11, printer magnet 12, 13, calling key 14 to ground.

The direction of current flow through the polar relay 10 at this time is such that its armature remains in the position' shown in Figure 1 so that the shunt circuit around the neutral relay 11 is open. Relay 11 is maintained energized and holds its armature 32 away from its back contact thereby maintaining the circuit of the motor 15 open.

Figures 2, 3 and 4 show stations similar to station A of Figure 1 and it is obvious that a large number of such stations may be interconnected through the exchange.

The connecting apparatus at the exchange for connecting any two stations together for telegraphic communication is illustrated in Figure 5. As shown in this figure, the apparatus comprises a plug 35, a jack 36, a printer magnet 37, a transmitter 38, a repeater 39, aplug and a jack 41, Figure 5. When the connecting apparatus is not in use, the plug 35 is kept in the jack 36 whereby a circuit extends from ground through resistance 42, contact 43, spring 44, relay and resistance 46 to negative battery. This circuit maintains the relay 45 energized so that its armature 47 is held out of engagement with its back contact 48 and the circuit of motor 49 is held open. A second circuit extends from negative battery through resistance 50. spring 51, plug 35, printer magnet 37, transmitter 38. repeater 39 and back to the tip of the plug 35 and over spring 52 and resistance 53 to ground. Similarly the plug 40 is kept in jack 41 which forms a circuit through the repeater 39. This circuit is required to control the repeater relays when the plug 40 is used for a message to the'central set.

Withdrawal of the plug 35 from the jack 36 breaks the engagement between contact 43 and spring 44 and deenergizes the relay 45 thereby permitting its armature 47 to move into engagement with its back contact 48 and closing the circuit of the motor 49, at the same time, the circuit for printer magnet 37 close switch 26 and at the same time arm 25 moves into engagement with lug 19 on spring 19. Closure of switch 26 operates any well known device for attracting the attention of the operator at the exchange.

The particular signal operated by shutter 25, advises the-operator which is the calling line. The operator then removes the plug 35 from the jack 36 and inserts it into the jack 17 which is connected with station A whereby the contact at the springs 18 and 20 is broken and a new circuit is formed from negative battery through resistance 21, long spring 19 of jack 17, ring 01E plug 35, printer magnet 37, transmitter 38, repeater 39, tip

'of plug 35, short spring 18, line 16, polar relay 10, neutral relay 11, printer magnet 12,

3 transmitter 13, key 14 to ground at Gr. It

will be noted that current over the circuit flows from negative battery at the central oiice instead of from positive battery through the line drop magnet 22 with the resa sult that the polar relay 10 operates its armature into engagement with contact 31 thereby shunting the neutral relay 11. Re-

lay 11 is now maintained deenergized independently of further opening and closing of D the line inasmuch as the signals thereafter transmitted are oi opposite polarity from the normal holding current.

Insertion of the plug into-the jack raises spring 19 and its lug 19 rocks shutter 25 counterlockwise until it is again latched by latch 24.

, y The party at the calling station A now opcrates the transmitter 13 to send impulses over the line 16 to the printerIna-gnet 37 at the exchange for indicating the desired called party and the operator at the exchange can respond by operating the transmitter 38 sending impulses'to printermagnet 12.

Should the party .at the calling station A desire to beY connected to another station as for example station B, (F'gure 2) the .exchange operator upon receiving this information will remove the plug 40 from its resting jack 41 and insert it into the-jack 17 which is connected with station B thus forming a circuit similar t0v that of plug 35. The relay 10 at station B will operate its armature 30 to close the shunt circuit around the neutral relay 11 deenergizing the latter. De- -energization of neutral relay 11 moves its Aautomatic telegraph devices.

:a local winding 86 and an armature 32 into engagement with its back contact and starts the motor 15. The attention of the party at station B may be attracted by the bell customarily associated with The station A will then be in communication with the station B through the repeater 39 and messages may be sent in either direction. The printer magnet 37 of the central oiiice is in series with the line connecting stations A and B and a record of all communication is made at the central oice.

It will be understood that if the calling party had indicated to the oprator that communication was desired with station C or D the operator would have inserted plug 35 in the jack 17 of the desired station.

The repeater 39 may be of the form shown in Figures 6, 7 or .10. In the form shown in Figure 6, the repeater comprises four relays 71, 72, 73 and 74, all being of the polar type and double wound.

The relay 71 comprises aline winding 75. local winding 76 and an armature 77 operating between contacts 78 and 79. The armature 77 is connected to one end of a high resistance 80, the other end of which is connected to ground. The contact 79 is connected to one end of a low resist-ance 81, the other end of whichds connected to negative battery.

The relay 72 comprises a line winding 85,

armature 87 operating between contacts 88 and 89. The armature 87 is connected to Vone terminal of the local winding 76 of relay 71 and to one terminal ofa high resistance 90, the other terminal of which is connected to ground. The Contact 89 is connected to one terminal of a. low resistance 91, the other terminal of which is connected to negative battery.

The relay 73 comprises a line winding 95, a local winding 96 and an. armature 97 operating between contacts 98 and 99. The armature 97 is connected to the tip of the plug no 35 and the contact 99 is connected to one terminal of the line winding of the relay 74.

The relay 74 comprises, line winding 105, a local winding 106 and u; an armature 107 operating between contacts 108 and 109; The armature 107 is connected to the tip of the plug 40 and the contact 109 is connected to one terminal of the line winding 950i the relay 73.

In operation, assuming that plug 35 has been inserted into the liack 17 whichconnects with station A and that the plug 40 has been inserted into the -j ack 17'which connects with station B and assuming further that the line 126 circuits 16 are closed at bot-h stations a line circuit will be established from negative battery, through resistance 21, spring 19, Aring of plug 35, line winding 85, line winding 105, contact 99, armature in addition to the 97 ,I the tip of vplug 35, 130

- mg and points of spring 18, line 16 leading to station A, windpolar relay 10, shunt wire of neutral relay 11, printer magnet 12, transmitter 13, key 14 to ground, A line circuit also will be' established from negatlve battery through resistance 21, spring '19, rlng of plug 40, line winding 75, line winding 95, contact 109, armature 107, t1p of lug 40, spring 18, line 16 leading to station polar relay 10, printer magnet 12, transmitter 18, key 14 to ground.

In addition to the line circuits, local c1r-' cuits will be established. One of these extends from negative battery through low resistance 81, contact 79, armature 7 7 local winding 86, local winding 106, low resistance 115 to ground. The other local circuit extends from negative battery through low resistance 91, contact 89, armature 87, local winding 76, local winding 96 and low resistance 116 to ground. The resistances 80 and 90 are high as compared with resistances 81 and 91. Resistances 115, 116, 117 and 118 are all substantially equal. These elements form a potentiometer system in wh1c h the direction of current in the local winding 1s determined by the position of the armature 77 in one circuit and armature 87 in the other. The potentiometer circuit is diagrammatically illustrated in Figure 6a.

ferring to Figure 6, when armature 77 is in engagement with contact 79, the dierence of potential between junction 125 and G is greater than the difference of potential between junction 126 and G and current w1ll therefore flow from negative batte to G from left to right through the Windlngs 86 and 106. When armature 77 is out of engagement with contact 79, the current will flow from right to left through the windings 106 and 86. The relative values of these two currents may be determined by adjustment of the value of the resistance 80.

e current in the line windings of the relays Hows in a direction tures 77, 87, 97 and 107 against their operating contacts 79, 89, 99 and 109 respectively and the current in the local windings flows in a direction to oppose the eiect of the line current. These currents are regulated so that the line currents dominate the local currents.

en the line 16 is opened at station A, current stops flowing in the line windings 105 and of the relays 74 and 72, respectively, and the current in the local windings 106 and 86 of these relays causes the armatures 107 and 87 to move out of engagement with their contacts 109 and 89 respectively. The opening of the contact at line 16 leading to the station B and deenergizes the line windings 95 and 75 of the line relays 73 and 71 respectively. Opening of the contact at armature 87 permits a reduced and reversed current to flow from negative bat- -key 14. The line 16 to hold the armato one terminal of the line armature 107 breaks the:

a Vresistance 118, local windings 96 and 6 of the relays 73 and 71, respec' tively, and through high resistance to ground, producing the same magnetic effect as produced by the line current inthese relays so that the armatures 77 and 97 of relays 71 and 73, respectively, are not moved but are held against'the contacts 79 and 99, respectivel In ordl'ar to send a break in signal, the operator at station B operates the manual from station B is thereupon opened. If this Occurs while amature 107 is out of engagement with its contact 109, no action will result until line 16 A is closed and armature 107 engages contact 109. Line 16 from station B bein o n at this time, windings and 75 will be deenergiz armature 97 will move out of engagement with its contact 99 thus holding line 16 to station A open and `a break in signal to station A.

Should line 16 at both stations be opened simultaneously, the relays will open their contacts, the two currents through the resistance 80 and 90 will tend to close all contacts and a vibratory condition will result but will be maintained only vibrate in synchronism, or until a line circuit 1s closed.

In the form of repeater shown in Figure 6. all of the local circuits are provided with but one source of current and with but one local winding in each of the relays` In the modified form of repeater, shown in igure 7,

tery, through mature 147 adapted to cooperate with a conu tact 148 which is connected through a resistance 149 to negative battery. The relay 133 comprises a line winding 155, a local Windfrom station so long as the relays.

ing 156 and an armature 157 adapted to cot operate with a contact with one terminal of the line winding of the relay 134. Relay 134 comprises, in addition to line winding 165, a local winding 166 and armature 167 having co-operative relation with a contact 168 which is connected winding 155 of relay 133. In addition to the four polar relays, a neutral relay is provided having 158 which is connected l an armature 176 cooperating with a contact :A

177. The armature 17 6 is connected with the armature 167 and the contact 177fis connected with the contact 168 so that when the armature 17 6 is in engagement with the contact 4through resistance 177 a shunt circuit is established around the armature 167 and its contact 168.

In operation, assuming that plug has been inserted into the j ac 17 which connects with station A andthat the plug has been inserted into the jack 17 which connects with station B, and assumingfurther, that the llne circuits 16 are closed at both stations, a line circuit will extend from negative potential,

21, ring of plug 35, print- 37, transmitter 38,-line windings er magnet y 145 and 155, contact 168, armature 167 ti of plug 35, line 16 leading to station A an continuing at station A through the polar relay 10, prlnter magnet 12, transmitter 13 and key 14 to'ground. A second circuit extends from negative battery, throu h resistance 21, ring of plug 40, line win 'ngs 135 and.165, contact 158, armature 157, tip of plug 40 and then over line 16 to station B and continuing at this station through polar relay 10, printer magnet 12, transmitter 13 and key 14 to. ground. In addition to these line circuits, two local circuits are established, one

- extending from negative battery through resistance 149, contact 148, armature 147, local winding 136, local winding 166 and through winding of relay 17 5 to ground. The second local circuit extends from negative battery' through resistance 139, contact 138, armature 137,1ocalwinding 146, local winding 156 and through winding of local relay 175 to currents are adjusted by resistances 139 and 149 so that the magnetic eiect of the current flowing through the line windings dominates the magneticV effect of the current flowing through the local windings. The line current tends to hold the armatures of the polar relays in engagement with their respective contacts and the local current tends to h old the armature 176 of local relay 17 5 away from its back contact 177.

When line 16 is opened at station A, the line windings 155 and 145 of therelays133 and v132, respectively, aredeenergized. Deenergization of line windings 155 and 145 removes the magnetic force which tends to hold the armatures 157 and 147 in engagement with their respective contacts. The local windings 156 and 146, being at this time energized over a local circuit, become eiective to move the armatures 157 and 147 away from their respective contacts. This local circuit extends from negative battery through resistance 139, contact 138, armature 137, local winding 146, local winding 156, winding of local relay 17 5 to ground. The movement of armature 157 away from its contact 158 opens the line 16 which leads to station B operating the printer magnet 12 at station B to register the opening of the line circuit 16 at station A. Movement of armature 147 away from its contact 148 breaks the local circuit which includes the local windings 136 and 166 of relays 131 and 134 respectively.

The local relay 17 5 will be held energized by current flowing through local windings 146 and 156 and through armature 137 of the relay 131. Any opening of the line circuit at stationB `subsequent to the opening of the line circuit at stat-ion A will be ineiective. The reclosing of the line at station `A will re.- close the contact at relays 132 and 133 and will restore the initial condition.

In the event that the called party at station B should happen to break in at the instant when the calling party at station A was beginning a break impulse, the windings 145 l* and 155 connected in series with the calling partys line are deenergized simultaneously with the windings 135 and.165 connected i series with the called artys line.

As a result of the eenergization of'windings 145 and 155 the local windings 146 and 156 become effective to o rate their res ective armatures 147 and lgetodisengage t eir contacts while at the same timeV the local windings 136 and 166 become effective to oper# ate their respective armatures 137 and 167 to disengage their res ective contacts. As a A result of the operation of these armatures, b oth the lines are openedjat the central station and both the calling and called party -would lose control. In orderv to reop'erate the system, someone would then have to go to the central station to reclose one of the party mes.

It is for this condition relay 17 5 is pro'- vided, the armature ofwhich controls a cir- 'cut shunting the armature-167 of relay 134.

Relay 17 5 is energized in two multiple circuits as described above. Under normal operations either one or the other of these loca-l circuits should be closed at all times. lf, however, both local circuits are opened due to thev simultaneous operation described above, relay 175 becomes deenergized. Its armature drops to its back contact shunting the armature 167 of relay 134 thereby closing the circuit at the central station for the line 16 extending to station A. When now the calling party of station A sends a. closing impulse by closing the circuitat station A, the line windings 145 and 155 are energized and since the magnetic eiect of these windings dominates the magnetic effect of the local windings, armatures 147 and 157 would move back into engagement with their respective contacts. Movement of armature 147 into engagement with its contact 148 recloses the local circuit including windings 136-and 166 and the local relay 175. Operation of armarepeating system thus will be placed under control of the called party at station B.

The operator at theexchange may desire to listen in on one of a plurality of circuits in operation. In such case an arrangement is l,

\ lig t the lamp 188.

.be plugged intoany link circuit. This ar rangement is illustrated in Fig. 8 in which the o erators telegraph set 178 is provided with plug 179 which may be connected into the Jack of any link circuit, 4as for example, the 4)gmk 180of the link circuit 181 shown in lpparatus may be provided at the exchange for indicating to the operator the condition of the line circuits. ne form of such apparatus is shown in Figure 8 in which a su rvisory line relay 182 is connectedin the o crates with a contact 184 connectin e winding of the slow relay 185. T e armature 186 of thelslow relay 185Y cooperates with' the contact 187 which 1s connected to a lam or other signal 188. Relay 182 responds to a current impulses in the line. The slow relay does not respond to telegra hic signals but will respond to the opening o the manual key 14 at the telegraph substation. When this key is operated to open the line circuit, relay 182 deenergizes and its armature 183 moves into engagement with the contact 184 closing a circuit for the slow relay 185. If the key 14 is held open for a sulicient length of time, the slow relay 185 willbecome energized and will move its amature 186 into en agement with contact 187 and thereby Y Obviously any other suitable signal device such as a buzzer may be substituted for the lamp 188.

A modified arrangement for switching the operators telegraph set into connection with any one of the -link circuits is illustrated in Figure 9. According to this modiiication a luralit of manual switches 190 are provi ed, eac comprisingcontacts 191 to 194, inclusive. The operators telegraph set 178 is permanently connected with the contacts 191 and 192 of all of the switches 190 as shown in Figure 9. Also, the contacts 193 and 194 ofeach manual switch 190 are connected respectively with one of the linl: circuits. The circuit of one'of the lines connected by the link 181 of Figure 9 includes the wire 170, the contact 194, the spring 171, the bridge wire 17 2,the spring 17 3,the contact 193, the wire 174, the repeater 189 and the supervisory relay 182. In order to connect the telegraphset 178 into one of the link circuits, without breaking the continuity of the operating circuit, it is 4only necessary to push the key 195 corresponding to that particular link circuit. This effects engagement between contacts 191 and 193 and simultaneous engagement between contacts 192 and 194 whereb the opterators tele aph set first is insertedI in series with the ink circuit 181. but shunted by the wire 172. The further movement of the switch 190 will break the shunt 172, rendering the set 17 8 effective.

If preferred a simplified form of repeater ne circuit and its armature 183 co-v with,

tion F. The-winding 203 of relay 201 has one of its terminals connected to one terminal of the winding 210 of relay 211, the other terminal of'winding 210 being connected over a resistance 212 to positive attery and over a resistance 213 to ground. The other terminal of the winding 203 is connected over a 1500 ohm resistance 214 to positive battery and to therarmature 215 of the relay 216. Thefront contact of this relay is connected to one Yterminal of the'winding 217 of relay 207 the other terminal of this winding being connected over a 500 ohm resistance 218 to ground.

The relay 207 has in addition to the winding 217 a winding 219 which has one of its terminals connected over a'1500 ohm resistance 220 to positive battery and over a 15'00 ohm resistance 221 to ground. The other terminal of the winding 219.s connected to one terminal of the winding 222 of the relay 216 and the other terminal of the winding 222 is connected to the armature 204 and over a 1500 ohm resistance 223 to positive battery. The front contact of relay 201 is connected to one terminal of winding 224 of relay 211 the other terminal of which is connected through a 500 ohm resistance 225 to ground. Thewinding 226 of relay 216 has one of its terminals connected through a resistance 227 to positive battery and the other terminal connected to the front contact of relay 211 and the armature 228 of relay 211 is connected over the line 229 to station E. It will be understood that the resistance values herein stated are for the purpose of illustrating comparative values and other desired constants may be substituted therefor in accordance with line conditions.

In operation, assuming that the line 229 at station E is closed, a circuit will extend from positive battery over resistance 227, line winding 2260i relay 216, front contact and armature 228 of relay 211 and over the line 229 to ground at station E. Current flowing through line winding 226 tends to maintain armature 215 in engagement with its front contact. A local circuit extends from positive battery through vresistance 220, winding 219, local winding 222, over armature 204 in engagement with its front contact, and through winding224 and resistance 225 to ground. A multiple circuit extends from lflO ance 225 to groun fthe line 209 to ground at station F rent flowing through 'positive battery over resistance 223, armature 204 and throu h winding 224 and resist- -A circuitv extends also from positivel battery over resistances 220 and 221 to ground. Since the resistance 221 is greater than -the resistance 225 the RI drop across resistance 220 is less than the RI drop across resistance 223. The potential at the point A will therefore, begreater than the potentialA at the point B producing a' flow of current from A, throu h the windings 219 and 222, to B. The ci? rent flowing through the local winding 222 is to move the armature215 away fromits vfront contact, whereas, as above stated, th@

ect'of the local curnow in vless thanv the RI drop through the resls'tance 212 so that the potential at point D 1s greater than the potential at the point C.

Accordingly a,local currentwill flow from D to C Ythrough the windings 203 and 210.

This local current is in the reverse direction effect of the line current flowing through the# Vfrom that which originally flowed through line winding 226 is to Vmove the armature 215 into engagement with its front contact, but the currents-are so adjusted that the line current dominates the local current and therefore the arinature 215 will be held in engagement with its front contact.

In a similar vmanner, assuming that the line 209 at station F is closed, a `circuit will extend romiositive battery over resistance 205, line win ing tact and armature 208 of relay 207 and yler to maintain armature 204; in engagement with its front contact. Also', a local circuit 'extends from positive battery through resistance 212, winding210, local winding 203,

over armature 215 in engagement with its front contact, and through winding 217 and resistance 218 to ground. A multiple circuit extends from positivebattery over resistance 214, armature 215 and through winding 217 and resistance 218 to ground. A circuit extends also from positive battery over resistances 212 and 213 to ground. Since the resistance 213 is greater than the resistance 218, the RI drop across the resistance 212 is less than the RI drop across resistance 214. The potential at the point C will, therefore, be greater than the potential at the point' D producing a flow of current roin C, through the windings 210 and 203, to D. The effect of the local current flowing through the local winding 203 is to move the armature 204 awav from its front contact, whereas, as

above stated, the elect of the line currentV flowing through the line winding 202 is to move the armature 204 into engagement with its front contact,.but the -currents are so adjusted that the line current dominates the local current and therefore the armature 204 will be held in engagement with its front contact.

When theline 229 is opened at the station the line winding 226 is deenergized and the current ing 222 becomes eiective to move armature 215 away from its front contact. Movement of armature 215 away from its front 202 of relay 201, front conline winding 202 tends flowing through the local wind- Y these windings and accordingly its eect engagement with their frontcontacts. In this .manner repeating back of the signal, to 'station E is prevented.

L When the line 229 is closed at station E,

the effect o this line winding dominates the effect of local winding 222 arma-ture 215 will bemoved back into engagement with its front Iclosing the circuit for thev 210 and 203.

and the current flowing through the to station F. Movement of armature 215 of potential between the points C and D. TheR'I drop through resistance 214 will be to holdthe armatures 204 and 228 in. i

. line windin 226 is again energized and slnce In Figure 11, I have shown a preferredV modification of the circuit arrangement shown in Figure 10. As in Figure 10, the repeater unit comprises four polarized relays 231 to 234. The relay 231 is. provided with windings 235 and 236 and an armature 237 operating between front and back contacts.

The winding 236 has one of its terminals connected through a resistance 238 to the positive side of a battery and has the other terminal connected vto the front contact of an armature 239 of relay 234, armature 239 being in turn connected to a conductor 241 which extends to a receiving mechanism 242 and transmitter 243 of any well known con-- struction, located at the east station.

The winding 235 of relay 231 has one of its terminals connected to the mid point of a potentiometer 244 which comprises two resistances of 1500 ohm resistance each connected to a battery at one terminal and to ground at the other terminal. The other terminal of the winding 235 is connectedover conductor 245 to the front contact of armature 246 of relay 233. Armatures 237 and 246 are both connected through resistances of 500 ohm each, -to ground and their front contacts are.. connected through resistances of 1500 ohms each to the positive side of a battery.

Relay 232 is also provided with mature 237. The winding 248 is connectedl to one side of the battery through a 4000 ohm resistance and at its other terminal to ground and is normally biased to hold its armature 252 in engagement with its frontA contact as will appear hereinafter. When the winding 247 is energized, the current 1n this Winding Hows in a reversed direction from that of the current Howing in winding 248 and will be of-suiiicient strength to throw the armature 252 to its back position against the action of the biasing winding.

The relay 233 is providedwith windings 253 and 254, having connections equivalent to those described for the relay windings 235 and 236 respectively, and windings 255 and 256 are connected in a'manner equivalent to the connections described for windings 247 and 248.-

In operation with the keys at each of the stations closed and all of the apparatus in normal condition, the current flowing through the biasing windings 248 and 256 of relays 232 and 234, respectively, are such as' to hold their respective armatures 252 and 239 in engagement with their front contacts. Current then Hows from ground at the west station through transmitter 260, receiver 259, armature 252 and its front contact through the winding or relay 233 and through the resistance 264 to ositive battery. The winding 254 is energized holding its armature 246 in engagement with its front contact.

Similarly a circuit is completed from transmitter 243 and receiver 242 at the east station, conductor 241, armature 239, and its front contact through the winding 236 and resistance 238 to positive battery. Relay 231 is energized and operates its armature 237 to engagement with its front contact.

Circuits are also completed for the windings 235 and 253, respectively, the circuit for the winding 235 extending from positive battery through lthepotentiometer 244 and through the winding 235 to the front contact of armature 246 at which point the cur-4 rent from positive battery Howing through the 1500 ohm resistance 263 forms a juncture therewith to How through the front contact and armature 246 and the 500 ohm resistance 265 to ground. The current flowing through winding 235 as a result of the above circuit is such as to tend to operate the armature 237 to its back contact,but is not stifficient to overcome the effect of the current through the winding 236 and accordingly the armature 237 remains in engagement with its front contact.

Similarly, the winding 253 is energized by current Howing from positive 1500 ohm resistance 266 and winding 253 to form a juncture with current How from battery through resistance 261. Current Howing through the winding 253 as a result of this circuit is in such a direction as to tend to make the armature 246 engage its back contact but is not suHicient to overcome the effects of the current How through the winding 254. 239 are accordingly all engaging their front contacts as described hereinbefore.

It will be assumed for purpose of illustration that the operator at the west station desires to communicate with the operator at the east station and to this end will operate his key 260 to open the signalling line 258. Current will cease to'How through the winding 254 and the current Howing in the winding 253 as described hereinbefore will now become effective to operate armature 246 to its back contact.

' As a result of movement of the armature 246 to its back Contact, an obvious energization circuit is completed for the winding 255 ofthe relay 234. The current in the winding 255 as a result of this circuit, Hows, it will be noted, in a reversed direction from that which Hows through the biasing winding 256 and the value of the current will be' greater than that in winding 256 as will be obvious from the smaller value of ohm resistance connected serially in the circuit as compared to the resistance connected serially to the Winding 256. As a result, relay 255 will overcome the effects of the biasing windin 256 and will throw its armature 239 to its ack contact, opening the circuit over conductor 241 extending to the east station and accordingly repeating the spacing impulse transmitted from the west station.

A further result of the operation of arma-- ture 246 to its back-contact is to cause a reversal in the direction of current Howin through the winding 235. It will be recalled that with armature 246 engaging its front contact, the current from positive battery Howing through 1500 ohm resistance 263 took the path of least resistance and over the front contact of armature through the 500 ohm resistance 265 and accordingly the current through winding 235 Howed from the positive battery and through potentiometer 244. When now the armature 246 disengages its front contact, the current from positive battery and resistance 263 Hows through winding 235 reversing the direction of current How through winding 235 and this winding which had previously been tending to throw armature 237 to its back contact now acts to aid winding 236 to hold armature 237 in engagement with its front contact. Armature 237 is accordingly prevented from disengaging its front contact so that relay 232 is not aH'ected and the im- The armatures 237, 252, 246, and' lll pulse is not repeated back over the line 2158.U ing line, means iniiluding circuit connections To transmita marking impulse, the operator at the west station recloses his key, and current again fiows through the winding 254 operating armature 246 to its front contact. The current through winding'235 is again in the same direction as origmally and the current for winding 255 is opened. so that the .winding 256 again becomes effective to operate its armature 239 into engagement with its front contact. Y

For signaling from the east station, similar operations occur. On receipt of each spacing impulse from the east station, winding 236 is open circuited and the winding 235 becomes eiective to throw armature 237 to its back contact, completing in turn an energizin circuit for the winding 247. Winding 24 when energized overcomes the eiect of the biasing winding 248, operatingarm'ature 252 to its back contactto repea e spacing impulse to the west station. At the Same time the movement or armature 237 to its back contact causes a reversal of current to flow through winding 253 and thereupon this winding aids the winding 254 in holding armature 246 in engagement with its front contact so that even though that winding 254 is opencircuited now, armature 246 remains in engagement with its front contact. For the transmission of a marking impulse from the east station, the line circuit 214 is closed, energizing the winding 236 which operates armature 237 to its front Contact again deenergizing winding 247 and the biasing winding 248 thereupon operates ar/mature 252 to its front contact repeating the marking impulse to the west station. The operation of armature 237 to its front contact again reverses the direction of the current through winding 253, so that this winding again tends to throw armature 246 to its back contact. At this time, however, the winding 254 is energized and armature 246 is held in engagement with its front contact.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What we claim and desire to secure by United States Letters Patent is 1. In a telegraph system, a first signaling line, a second signaling line, a repeater interposed therebetween comprising a pair of relays individual to each of said signaling lines, a pair of windings in each of said relays one of said windings of one of said relays being connected in series with its associated signalcontrolled by said one relay for operating saidsecond relay and means including circuit connections controlled by said one relay for preventin operation of said other relay associated wit said other signaling line.

2. In a telegraph system, first and second signaling lines, a two-way repeater. interosed therebetween comprising a pair of reays associated with each of said signaling lines, circuit connections whereby one of said relays is operated under control of si als received over one of said signaling ines, means including circuit connections whereby said operated relay controls the other of a pair of relays and means including circuit connections whereby said relays associated with the other of said signaling lines are rendered nonresponsive.

3. In a telegraph system, a first signaling line, a second signaling line, a two-way repeater associated with said signaling lines, said two-way repeater comprising a line responsive relay and a repeater relay associated with each of said signaling lines, means including circuit connections whereby said line responsive relay responds to impulses received over one of said lines, means including signaling circuits whereby said repeater relay is operated in accordance with the operation of the line responsive relay and means including circuit connections whereby the relays associated with the other of said signaling lines is rendered non-responsive to said impulses.

4. In a telegraph system, a rst signaling l1ne, a second signaling line, a line responsive relay and a repeater relay associated with each of .said signaling lines, each of said line responsive relays comprising a winding conn ected in series with one of said signaling lines over the armature of the repeater relay assoclated with the other signaling line and comprising also a second winding connected 1n serles with a winding on said repeater relay and under control of the armature of the line responsive relay associated with the other. of said signaling lines, each of said repeater relays comprising a second winding controlled by the armature of one of said line responsive relays, means .including circuit connections whereby the electro-magnetic action of the line windings of the line responsive relays overcomes the magnetic eiect of the local windings thereof, means for operat- 1ng one of said line relays in accordance with impulses transmitted over one of said lines, means including circuit connections responsive to the operation of said line responsive relay for repeating said impulses over the other of said lines and a second winding assocated with the other of said line responsive relays for reversing the'magnetic eiect of the local winding thereof, whereby said line responsive relay is nonresponsive to said re- 4lines over the amature of the repeater relay associated with the other signaling line and comprising also a second winding connected in series with a winding on said repeater relay and under control of the armature of the4 line responsive relay associated with the other of said signaling lines, each of said repeater rela s comprising a second winding controlfed by the armature of one ofY said line responsive relays, means including circuit connections whereby the electro-magnetic acltion of the line windin of the line responsive relays overcomes t e magnetic eiect of the local windings thereof, means for operating one of said line relays in accordance with impulses transmitted over one of said lines and means including circuit connections responsive to the operation of the said line responsive relay for repeating said impulses over the other of said lines.

6. In a signalingsystem; a first circuit; a second circuit; a repeater comprising a relay having two windlngs, one of said windings being connected to a continuously closed circuit for normally biasing said relay; and a receiving relay for controlling the circuit f'or the second of said windings, the receiving relay comprising a winding connected in the second circuit and a second winding connected in a local biasing circuit.`

7. In a signaling system; a first circuit; a second circuit; a repeater comprising a relay having two windings, one of said windings being connected to a continuously closed circuit for normally biasing said relay; a second relay for controlling the circuit for the vsecond of said windings; the second relay comprising a winding connected in Said second circuit and a. second winding connected in a. local biasing circuit; and means for reversing the direction of current in the second winding of said second relay.

8. In a signaling system; a first circuit; a second circuit; a repeater comprising a relay for each of said circuits, each relay having two windings, one of said windings being connected to a continuously closed circuit for normally biasing said relays; a receiving relay individual to each circuit for controlling the circuit; for the second of said windings; each receiving relay comprising a winding connected in said circuits and a second winding connected in a local biasing circuit; and means for reversing the direction of current in said second receiving relay windings,

said means comprising the receiving relayv associated with t e other circuit. v

9.-In a telegraph re ater, a first polar relay, a first local circuit throu h said lar relay, a first line-circuit contro ing sai po- 7g lar relay, a first signal-sending -relay controlled .by said polar rela a second line-circuit controlled by said rst signal-sendin relay, a second polar rela a second loca circuit throu h said secon lar relay, said second line-circuit controlling said second lpolar relay, a second si al-sending relay controlled by said seconnpolar rela and \controlling said first line-circuit where y oneI said line-circuit may control a said polar relay to control a signal-sending relay to send a signal upon the other line-circuit, and means whereby each said polar relay controls the local circuit of the other polar relay to prevent reiection signals. Y

10. In a telegraph system, two signaling lines, a repeater comprisin a pair of polar signal-receiving relays one lndividual to each si aling line, a pair of windings on 'each o said relays, one of said windings in each of said relays being connected in series with one of said lines, the second winding of each of said relays being connected in a local circuit controlled by the other of said relays, and a second palr of relays whose circuits are entirely local for repeating signals received by said polar relays.

11. In a telegraph system, a first signaling line, a second signaling line, a repeater interposed therebetween comprising a pair of polar relays one individual to each of said 'signaling lines, a pair of windings in each of said relays one of said windings of each of said relays being connected in series with its associatedsigna-ling line, means including circuit connections controlled by one of said relays for restraining the other of said relays and a further relay for each said line for repeating signals into the other line.

12. In a telegraph repeater, two polar receiving relays, biasing circuits for each relay comprising each an unbalanced Wheatstone bridge circuit, each receiving relayoperative to reverse the balance of the bridge circuit of the other relay, each relay being inoperative when its own bridge circuit is reversed in balance, two lines controlling said two polar relays respectively and two signalrepeating relays each controlled by a polar relav and each controlling a line circuit.

13. In a telegraph system, a first line Icircuit, a second line circuit, polar receiving relays. one for each circuit, biasing windings one for each relay, means whereby the operation by one line circuit of either receiving relay opens the other line circuit and reverses the bias of the other receiving relay, said means comprising in part unbalanced lll Wheatstone bridge circuits, each bridge conl trolled by one of said receiving relays and containing the biasing winding of the other receiving relays, sendmg relays one for each line circuit and each controlled by the polar relay of the other line circuit. Y 14. B1 a telegraph repeater, a first normally closed line circuit, a polar receiving relay controlled by said line circuit, a polar signalrepeating rela controlled by normally open points of sai polar receiving relay and a second normally closed line-circuit controlled by normally open points of said polar signalrepeatin relay, whereby the mechanical transit tlme of the amature of said polar receiving relay dela s the repeating of a line-opening signal-clilange andthe mechanical transit time of the armature of said polar si al-repeating relay delays the repeating o aline-closing signal-change and whereby 20 with symmetrically adjusted relays the time length of any signal will be unchanged by the repeater. 5

In testimony whereof I aix my si ature.

s JOHN O. C R. 5 In testimony whereof I aix m si ature.

- ABRAHAM S. BElgJ 

